Winter can be a difficult time for car owners. While cold weather negatively affects electric vehicle batteries and internal combustion engines, EV drivers have specific concerns.
But don’t count these cars out for your winter driving. One couple even took their electric SUV from the Arctic to the South Pole, finishing their trip this past December. Talk about cold weather.
Cold weather drains EV batteries because there is a low-voltage and high-voltage battery. The low-voltage 12V battery can lose charge on cold days like in cars with internal combustion engines. However, EVs can’t quickly charge until this battery has been jump-started.
Lithium batteries can be negatively affected by the cold, which decreases driving range. More electricity is needed during the cold to run the heater, defroster and other systems. According to Consumer Reports, range starts to drop at 40°F. Cold weather also saps about 25% of range when traveling at 70 mph compared to mild weather.
In addition, the anode and cathode—the two sides of the battery—have chemical reactions that are slowed during cold temperatures, which affects charging speeds. In a gas engine, about 10% of the energy is used for forward momentum. In EVs, it is 90%. EVs built with heat pumps for warming interiors will have less battery strain in cold weather. Newer vehicles are likely to have these efficient heat pumps, but older models are not.
Scott Case, the CEO of Recurrent, a company that measures EV battery performance, estimates that vehicles with heat pumps lose about 20% of range in extreme weather, while those without heat pumps lose 40%.
“There’s not a lot of waste heat that you can just use to warm up the cabin,” Case said.
What can drivers do?
According to EV manufacturer Tesla, if drivers see a blue snowflake on the touchscreen, the battery is too cold for full power. Users may notice “reduced regenerative braking and acceleration.” The company recommends leaving the EV plugged in and keeping the charge level above 20%. Users can drive, charge and precondition to warm the battery.
Consumer Reports recommends drivers use the popular departure scheduling feature on an app or have the car preheat before driving. Lowering the cabin temperature and preconditioning the battery before DC charging are also suggestions.